Dynamics in the emergence of dormant and non-dormant herbaceous species from the soil seed bank from a Brazilian dry forest. (4th March 2020)

• Record Type: Journal Article
• Authors: de Souza, José Djalma; de Souza Aguiar, Bruno Ayron; dos Santos, Danielle Melo; de Araujo, Vanessa Kelly Rodrigues; Simões, Júlia Arruda; de Andrade, Juliana Ramos; de Lima Araújo, Elcida
• Editors: Zhang, Wen-Hao
• Is Part Of: Journal of plant ecology. Volume 13:Number 3(2020:Jun.)
• Page Start: 256
• Page End: 265
• Publication Date: 2020-03-04
• Subjects: establishment -- herbaceous species -- physical dormancy -- seed bank -- seed germination -- semiarid; 草本植物 -- 半干旱 -- 种子萌发 -- 植株建立 -- 物理休眠; Plant ecology -- Periodicals; Phytogeography -- Periodicals; 581.705
• DOI: 10.1093/jpe/rtaa008
• Languages: English
• ISSNs: 1752-9921

Abstract

Abstract: Aims: In dry tropical forests, herbaceous species may have dormancy mechanisms and form persistent and transient seed banks in the soil. Evolutionarily acquired, these mechanisms are efficient for the establishment and survival of these herbs, especially in forests with unpredictable climates, such as the Caatinga. Thus, our objective was to verify whether the studied herbaceous species adopt the physical dormancy mechanism and how these natural barriers are overcome, to understand the temporal dynamics existing in the soil seed bank from a Brazilian dry tropical forest. Methods: Seeds of five native herbaceous species from the Caatinga forests were selected and submitted to pre-germinative treatments for verifying the presence of physical dormancy. We collected soil samples in the rainy and dry seasons for four consecutive years and monitored the emergence of the selected herbaceous in the greenhouse. We verified the differences in germination and seed bank emergence in the soil by generalized linear models. Important Findings: The presence and absence of physical dormancy were observed in seeds from Caatinga herbaceous species. We found intraspecific and interspecific differences in the herbaceous emergence from soil seed banks between years and climatic seasons. In perennial herbs, consecutive lack of emergence between seasons and years was frequent, which suggests a direct relationship with the mechanism of physical dormancy and the environmental conditions necessary to overcome integument barriers. In these species, seed dimorphism and dormancy may confer additional advantages to their survival. Moreover, presenting intermediate levels of physical dormancy in an annual species may be an evolutionary adjustment to rainfall unpredictability. In contrast, we found that the annual herb without dormancy is more sensitive to seasonal and interannual climate changes, as evidenced by the increase and significant reduction of its emergence in the soil seed bank. These differences acquired evolutionarily are advantageous for the establishment of herbaceous populations, mainly in semiarid regions with an unpredictable climate.